This invention relates to an induction system for an internal combustion engine and more particularly to an improved throttle arrangement for such an engine.
Recently it has been found that the combustion efficiency of an internal combustion engine may be significantly improved by supplying the idle and low speed mixture requirements of the engine to the cylinders through a sub or auxiliary intake system that has substantially less cross-sectional area than the main induction system. As the load on the engine increases, an increasing proportion of the mixture is supplied to the chambers through the main induction system in accordance with this invention. By introducing the low speed mixture to the engine through a small induction passage, turbulence and, if desired, swirl is generated in the chamber at the time of ignition. This causes more rapid flame propagation and an improvement in both fuel economy and a reduction in the emission of unwanted exhaust gas constituents. In connection with such an arrangement, a pair of throttle valves are incorporated that control both the total mixture flow and the amount of flow through the main induction passage.
In order to fully enjoy the benefits of this type of system it has been found desireable to accurately control the sequence of operation of these throttle valves.
It is, therefore, a principal object of this invention to provide an improved induction system for an internal combustion engine.
It is another object of the invention to provide an engine induction system embodying a main and auxiliary induction system having accurate flow control through the respective induction systems.
It is a still further object of this invention to provide an improved throttle control system for the induction system of an internal combustion engine.